Known apparatuses for depositing solids from an air current (EP 0 192 803) are provided with a bucket wheel lock, in the built-in drum of which a bucket wheel, which takes up an air current, is rotatably supported at the connection side. Coarsely particulate and finely grained solid particles are conveyed into this built-in drum over the connecting opening and the coarse particles are deposited by means of a screen, which forms the boundary of the built-in drum at the wall. The air current, still containing the dust-like fine particles, is passed over a pipe connection which, in the direction of the current, is behind the screen, into a dust filter, which must be cleaned at intervals.